Natural resources such as gas and oil can be recovered from subterranean formations using well-known techniques. The processes for preparing a well bore for the recovery of such resources often employ various well bore servicing fluids. One example of such fluids is hydraulic fracturing fluid, or “frac fluid”.
Frac fluids are employed in hydraulic fracturing, which is a common stimulation technique used to enhance production of fluids from subterranean formations in, for example, oil, gas, coal bed methane and geothermal wells. In a typical hydraulic fracturing treatment operation, a viscosified fracturing fluid is pumped at high pressures and high rates into a wellbore penetrating a subterranean formation to initiate and propagate a hydraulic fracture in the formation. Subsequent stages of viscosified fracturing fluid containing particulate matter known as proppant, e.g., graded sand, ceramic particles, bauxite, or resin coated sand, are then typically pumped into the created fracture. The proppant becomes deposited into the fractures, forming a permeable proppant pack. Once the treatment is completed, the fracture closes onto the proppant pack, which maintains the fracture and provides a fluid pathway for hydrocarbons and/or other formation fluids to flow into the wellbore.
The use of slick water fracturing fluids, which employ a friction reducer, but which often do not employ a viscosifying agent, is well known in the industry. Most friction reducers used in slickwater fracture stimulation are high molecular weight polyacrylamides in water based mineral oil emulsions. However, at the concentrations of friction reducer typically employed in slickwater fracturing fluids, which concentrations typically range from about 0.5 gpt to 2 gpt, it is believed that the mineral oil and polyacrylamide in the emulsions can cause a buildup of polymer cake residue that can damage the well formations. For this reason, breakers are sometimes introduced into the slick water fracturing fluids to reduce the size of the polymer chains, and thereby potentially reduce fracture and formation damage.
Well servicing fluids that contain water, such as frac fluids, can also damage some well formations due to adverse water saturation effects, which can include what is known as sub-irreducible water saturation. When exposed to aqueous based fluids, these formations will trap water for long periods of time (e.g., permanently). The saturation of the formation with water can result in reduced permeability to hydrocarbons, which in turn can cause reduced productivity of the well.
These water retention issues are not limited to fracturing fluids, but can result from any well servicing fluids that are aqueous based, including those used during drilling, completion and workover operations. For formations that are not compatible with water, the use of these aqueous based fluids can be a major cause of productivity impairment in hydrocarbon wells.
Thus, there exists a need for improved well servicing fluids that can reduce or eliminate one or more of the problems discussed above.